Microorganisms play a vital role in litter decomposition in headwater streams, yet the influence of litter type on microbial communities during decomposition remains unclear. We investigated microbial community dynamics during the decomposition of Pinus massoniana flower and twig litter using litterbags with varying mesh sizes (0.04, 0.5, 2, and 5 mm) in subtropical forest headwater streams. We found that (1) microbial communities followed distinct successional patterns, with alpha diversity increasing over time and clear stage-specific shifts in composition. Bacterial communities were more influenced by time, while fungal communities responded mainly to substrate type; (2) flower litter supported higher microbial diversity and more complex interaction networks than twig litter. Proteobacteria and Ascomycota dominated bacterial and fungal groups, respectively, with differences in abundance and temporal trends between litter types. (3) certain microbial taxa correlated strongly with decomposition rates; key ASVs affiliated with Chromobacteriaceae , Bacteroidia , and Thauera were identified as important drivers. Aquatic invertebrates enhanced decomposition during mid- to late stages, but had limited effects on microbial community structure. Overall, these findings provide new insight into microbial succession, interaction networks, and their roles in regulating litter decomposition in headwater stream ecosystems.
Chen et al. (2026) studied this question.